File Sharing Patent Fracas: Altnet Sues Streamcast Over Patent

from the some-background-here dept

There's an awful lot of history that goes into this story, and it's difficult to cover it all in a single blog post -- but we'll try to do the quickie version. Kazaa was a company, founded by the two guys who later went on to found Skype. Early on, they licensed the underlying technology to a company called Streamcast that offered a popular file sharing app called Morpheus. As the heat from the RIAA on Kazaa grew, the two guys apparently sold Kazaa off to a complicated shell of a company called Sharman Networks. Around the same time, they cut off Streamcast, breaking most installations of Morpheus. Soon afterwards (or at the same time, depending on whose story you believe), Sharman teamed up with another company, called Brilliant Digital, which had a technology called Altnet. Altnet piggybacked on Kazaa installations (in a sneaky early form of adware bundling), trying to include a "legal" file sharing system that would pop up legal versions of songs you could buy. The recording industry claimed that Altnet was really a front for the people who truly controlled Kazaa, though that was never proven. However, in the midst of all this, Altnet surprised plenty of folks in the file sharing app business by announcing it held a patent on using a hash to identify files (something plenty of folks would claim was not particularly unique at the time). They started threatening to sue other file sharing companies which didn't win them many friends with folks who should have been their natural allies. Even suing the RIAA for violating this patent in trying to track file sharing didn't seem to get them very far.

Fast forward a few years, and Streamcast is still miffed about Kazaa/Sharman/whoever cutting all its users off from the underlying FastTrack network. Suddenly, they come out and claim that, despite all the buzz, Kazaa and FastTrack never really used a distributed network, but a centralized one. That didn't get much traction, so earlier this year, the folks at Streamcast claimed that the whole big confusing shell was really a big ruse to keep them from owning the core technology behind Kazaa, which they claim later went into Skype. With all this general animosity and lawsuits, it was only a matter of time before another one got thrown onto the pile. Now that Sharman has finally agreed to pay up and go straight (thanks to millions of dollars in pocket change from Skype's founders), Altnet is back in the news suing Streamcast for patent infringement over the hash identification system. As the article notes, fewer and fewer file sharing systems are making use of such a method any more anyway (whether or not the underlying patent is valid) -- and no matter what the actual connection is between Altnet, Kazaa and Sharman, this seems like a move that's in response to some of these other disputes rather than any real concern over patent infringement.

Re: Re: hashes?

BTW - This isn't at all like one criminal suing another over use of the same door jimmy-ing technique, right?

Uh... No. Criminal maybe. Door jimmy-ing no. Hashing is a term for a variety of techniques for identifying/mapping entities in an arbitrary datastructure.

Your personnel number might be an example of a hash result, somehow someone mapped a number to your name, and now you're a number in a database, the process of mapping (be it a sequential process or whatever) is referred to as hashing.

Hash

Hashing is a coding method where random items are categorized in a table.

When your brain looks for an entry in the phone book it organizes the words by going letter by letter until it finds a slot where that word fits. This process of taking arbitrary/random items (words) and hashing it (sorting the word by letters then locating and placing them in a specific manner in a table).

CRC Checking

#3 and #4

A hash is a minor representation of a greater, always built by pieces of the greater.

A thumbnail of a picture could be considered a hash (because its a minor derivitive of a greater). The filename could be one index.

In the computer world, usually creating a hash is a mathematical process that involves merely XORing the bytes of a file until you only have n bytes left (where n is your hash size). but other algorithyms can be used to increase the complexity making the hash a more obscure refernce (security).

Theoretically, the hash will be unique and never repeated. However, thats not actually possible. given this "almost uniqueness" and the fact that the hash result is usually a nice hex code (number), it ALSO makes a great index for databases.

And yes, #5 is right, CRC is a form of hashing (but on a far smaller/lighter scale). AFAIK, crc was first implemented in the days fo the 8080 processor to verify that memory register contents didnt get corrupted by bad timing circuits. crc validation failures always resulted in crashing the core. nowadays, its just used by linux folks to verify that files downloaded unharmed. (ok, that was biased, sorry)

CRC is never used as an index however, it is only used to verify files did not get corrupted during transfers.